1. Field of the Invention
The invention pertains to a mounting rail for holding and positioning a sealing strip, the rail being provided with attachment devices, which are arranged along one of the long sides of the mounting rail and which are separated from each other by gaps. These types of mounting rails are used in particular in systems for applying self-adhesive sealing strips to the doors of motor vehicles.
2. Description of the Related Art
The sealing strip for a motor vehicle door is applied by arranging its self-adhesive surface around the periphery of the door and by then pressing it down. The automated steps of applying and pressing down the sealing strip are carried out by an application system for self-adhesive sealing strips, which comprises a plurality of mobile units, each with its own contour element, wherein each mobile unit can be moved back and forth in a direction essentially perpendicular to its assigned section of the adhesion surface on the door of the motor vehicle. Because, at least in some cases, the mobile units move in different directions, each mobile unit has its own mounting rail, which can be moved independently of the mounting rails of the neighboring mobile units.
To install the sealing strip, it is first set down onto the mounting rails arranged around the periphery of the door and held in place by a support element such as an undercut. Then the entire application system, including the mobile units, is moved toward the vehicle door until the mobile units, with the sealing strip mounted on them, are located a defined distance away from the adhesion surface of the vehicle door. Then the self-adhesive surface of the slightly expanded sealing strip is moved toward the adhesion surface and positioned here. Finally, the sealing strip is pressed against the adhesion surface on the door by pressing devices at a defined pressure.
The applicant's application systems of this type for sealing strips have been in use in the automotive industry since 1987. At the beginning, the individual mounting rails were made of spring plate. One of the long sides of each plate was provided with comb-like slots extending from the side, whereas holes were provided along the other long side, so that the mounting rail could be screwed to the contour elements carried on the mobile units.
In some cases, the flexibility of the known mounting rails made of spring plate and provided with comb-like slots was no longer sufficient as the contours of motor vehicle doors and thus the contours of the adhesion surfaces became more complicated. In modern door geometries, especially in the transition area to the window frame, the mounting rails can lack sufficient flexibility, especially in the plane of the mounting rail.
To avoid the need to fabricate individual and therefore expensive mounting rails for these types of problem areas, a mounting rail is described in EP 0 849 106 B1, which consists of a continuous strip of plastic material with a serpentine shape when looked at from above. The serpentine-shaped strip comprises attachment devices along one of its long sides, these devices being separated from each other by gaps, whereas, on the other side, the legs and webs of the serpentine-shaped strip form spring tongues. The sealing strips to be applied are set down onto the spring tongues. Because of the serpentine shape of the continuous strip, the mounting rail is extremely flexible and fits any door contour, even in the problem areas which demand a high degree of flexibility from the mounting rail. The flexibility attributable to the serpentine shape makes it possible to lay only a single continuous mounting rail over the contour elements and to screw it in position there as usual.
The advantage of the high flexibility attributable to the serpentine shape, however, is obtained at a certain cost; that is, it leads to the disadvantage that it can be difficult to set the sealing strip down onto the spring tongues, because, over the course of time, the spring tongues may no longer line up properly with each other because of material fatigue. Material fatigue in combination with the high flexibility of the serpentine-shaped mounting rail, furthermore, can also lead to an unequal pressure distribution when the self-adhesive strip is pressed onto the adhesion surface.